1. Field of the Invention
The present invention relates to medical device connectors, and more particularly to optical catheter connectors.
2. Background
Optical Coherence Tomography (OCT) is an optical imaging technique, which achieves non-invasive, cross-sectional imaging of a patient""s body. OCT is analogous to ultrasound imaging, only measuring the intensity of back-scattered infrared light rather than ultrasound. To image the blood vessel of a patient using OCT, an optical catheter is inserted into the blood vessel. An optical signal is transmitted through an optical fiber in the optical catheter and emitted at the distal end of the catheter into the blood vessel. The optical signal is typically produced by a laser, e.g., laser diode. The optical signal reflected back to the catheter from the blood vessel and surrounding tissue is transmitted through the optical fiber to an interferometer, which optically processes the reflected optical signal to obtain a depth image of the blood vessel.
An OCT connection system couples optical signals produced by a light source, e.g, laser, into the catheter optical fiber to be emitted inside the body. The OCT connection system then couples the reflected optical signal out of the catheter optical fiber to an interferometer to obtain a image of the inside of the body. In addition, the OCT connection system may include a motor unit for providing drive torque to the catheter optical fiber to rotate the catheter optical fiber during imaging. This enables a radial cross-sectional image of the inside of the body to be obtained.
There are many challenges in designing a high performance, ergonomic catheter connector. The requirements of a good connector design include sterile field maintenance, reliable high performance components, ease of assembly and an intuitive connection procedure. A good design should provide a connection system that meets all these requirements while keeping the cost of the disposable portion of the connector low. The design should provide a positive lock between a catheter connector and a motor unit to prevent accidental disconnection of the catheter or degradation of performance if the catheter is used to pull the motor unit. It should also provide a clear indication that proper engagement between the catheter connector and the motor unit is achieved.
The invention provides an OCT connection system comprising two mating assemblies, a motor unit and an OCT catheter connector. The OCT catheter connector mates to the motor unit for coupling optical signals into and out of a catheter optical fiber and for providing drive torque to the catheter optical fiber.
A motor unit, built in accordance with a first example embodiment of the invention, includes a motor nose with an opening at its distal end, a rotary shaft housed in the motor nose, a connector assembly housed in and attached to the rotary shaft, and a fiber-to-fiber adapter mounted to the rotary shaft. The rotary shaft, the connector assembly and the fiber-to-fiber adapter all rotate together within the motor nose and form the mechanical rotating portion of the motor unit. The motor unit further includes a motor optical fiber that runs along the rotational axis of the connector assembly. One end of the motor fiber is supported by a motor fiber ferrule, which is inserted into one end of a split sleeve in the fiber-to-fiber adapter. As used here, the term xe2x80x9cferrulexe2x80x9d refers to a hollow structure of any shape or configuration. For example, while preferably the motor fiber ferrule is cylindrical, it can be hexagonal. As another example, a motor fiber ferrule may be a hollow band surrounding the motor optical fiber and protects or gives support to the motor optical fiber.
The OCT catheter connector includes a catheter ferrule with an opening at its proximal end, a connector bushing rotatably housed within the catheter ferrule, and an optical fiber catheter connector attached to the connector bushing. The OCT connector also includes a catheter optical fiber that runs along the rotational axis of the catheter fiber connector. One end of the catheter optical fiber is supported by a catheter fiber within the catheter fiber connector.
The OCT catheter connector is mated to the motor unit by inserting the fiber connector into the fiber-to-fiber adapter through the opening in the motor nose. As the fiber connector is inserted into the fiber-to-fiber connector, the catheter fiber ferrule supporting the catheter optical fiber is inserted into the other end of the split sleeve in the fiber-to-fiber adapter. The split sleeve aligns the catheter optical fiber with the motor optical fiber to couple optical signals between the two fibers. The fiber-to-fiber adapter includes retaining clips for locking the catheter fiber connector in place once proper engagement is achieved. The opening of the motor nose is equipped with tab slots adapted to receive snap lock tabs on the OCT catheter connector. Once the OCT catheter connector is properly mated to the motor unit, the rotary shaft provides drive torque to the catheter fiber connector and the catheter optical fiber via the fiber-to-fiber adapter.
The snap locks of the OCT catheter connector may include grippers for pushing the catheter fiber connector into proper engagement with the fiber-to-fiber adapter. To do this, the grippers engage slots on the connector bushing through slot openings in the catheter ferrule. This engagement holds the connector bushing stationary with respect to the catheter ferrule so that the connector bushing pushes the catheter fiber connector into the fiber-to-fiber adapter as the OCT catheter connector is inserted into the motor unit. When proper engagement is achieved, the grippers retract from the slots on the connector bushing, allowing the catheter fiber connector to freely rotate within the catheter ferrule of the OCT catheter connector.
The OCT catheter connector may include an xe2x80x98Oxe2x80x99-ring fitted around a grooved portion of the catheter fiber connector to provide a dynamic seal to block fluid from contaminating the catheter fiber connector. The OCT catheter also may include a free floating xe2x80x98Oxe2x80x99-ring housing to compensate for any eccentric rotation of the catheter fiber connector.
An OCT catheter connector, built in accordance with a second example embodiment, comprises a flexible catheter ferrule and a rigid retainer within the catheter ferrule. The retainer provides rigidity to the catheter ferrule. The OCT catheter connector also includes a connector bushing and a catheter fiber connector attached to the connector bushing. The connector bushing may include ribs that are positioned at cutouts in the retainer.
The OCT catheter connector according to this second example embodiment is mated to the motor unit by slightly squeezing a grip area of the catheter ferrule corresponding to the cutouts of the retainer. The squeezing deforms the catheter ferrule within the grip area, causing the catheter ferrule to contact the ribs of the connector bushing through the cutouts in the retainer. This contact holds the connector bushing stationary with respect to the OCT catheter connector so that the connector bushing pushes the catheter fiber connector into engagement with the motor unit as the OCT catheter connector is inserted into the motor unit. Once the OCT catheter connector is properly mated to the motor unit, the catheter ferrule elastically regains its original shape, allowing the connector bushing and the catheter fiber to freely rotate within the catheter ferrule.
The OCT connector according to this second example embodiment also preferably includes a shield running around the outer cylindrical surface of the catheter ferrule to help maintain a sterile field by forming a barrier between a clinician""s sterile hand, which holds the OCT connector, and the non-sterile motor unit. The OCT connector also may have short ribs on the outer cylindrical surface of the catheter ferrule to snap into mating grooves in the motor unit to prevent unwanted disconnection of the OCT connector from the motor unit.
A motor unit, built in accordance with a third example embodiment, includes three spring loaded ball plungers radially located preferably 120 degrees apart on the motor nose. Each one of the three ball plungers has a spherical ball positioned to engage a corresponding concave depression in the OCT catheter connector to secure the OCT connector to the motor unit via frictional resistance. The motor nose further may include a bendable wave or Belleville washer surrounding the fiber-to fiber adapter of the motor unit.
To insert the OCT connector into the motor unit, the catheter ferrule of the OCT connector is pushed into the motor unit. As the catheter ferule is pushed into the motor unit, the distal end of the connector bushing contacts a portion of the inner wall of the catheter ferrule. This contact causes the portion of the inner wall of the catheter ferrule to push against the connector bushing, which in turn causes the connector bushing to push the catheter fiber connector into engagement with the fiber-to-fiber adapter of the motor unit. Also during insertion of the OCT connector into the motor unit, the proximal end of the catheter ferrule pushes the washer surrounding the fiber-to-fiber adapter inwardly. When the catheter ferrule is released after proper engagement has been achieved, the washer pushes the catheter ferrule distally with respect to the connector bushing. This causes the portion of the inner wall of the catheter ferrule to move away from the connector bushing, allowing the connector bushing to rotate freely within the catheter ferrule without friction or side loading.
The catheter ferrule according to this third example embodiment may be constructed of a rigid, injection moldable material as one piece or two pieces comprising a shield that is bonded to the cylindrical body of the ferrule that acts as a sterile barrier to prevent the contamination of the clinician""s sterile hand during attachment of the catheter to the non-sterile motor unit.
The OCT connector according to this third example embodiment may include drain holes to allow fluid leakage to drain through the wall of the ferrule to reduce the likelihood of contamination of the motor unit and the fiber optic connector if the xe2x80x98Oxe2x80x99-ring seal should leak during high-pressure infusion. In addition, the xe2x80x98Oxe2x80x99-ring according to this embodiment seals around a gland instead of a grooved portion of the catheter connector. The gland is a stainless steel tube with a smooth outer surface finish that is bonded into the catheter fiber connector using epoxy to form a high pressure seal.
The details presented in this Section are provided as illustrative examples only, are not necessarily required by the invention and should not be used to limit the scope of the invention. Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.